Imitating a bird call by blowing through the hands is a fun if relatively useless skill. Perfecting the call can take a considerable amount of time and be quite frustrating. A dedicated student should be able to produce some sound within an hour.
Place hands in a prayer position with palms together. From this position the hands will be moved to form the necessary airtight cup for the bird call to be made.
Rotate the right hand away from the body 90 degrees, keeping the palms together. This movement should place the hands in a position similar to a closed clap.
Grip the hands together to create an airtight cup. Squeezing the cupped hands together you should hear and feel air being forced in and out of the space between the palms. This is a good way of being sure your fingers are airtight.
Move thumbs so they are vertical and parallel to each other, creating a small gap between the knuckles. This gap will be the hole through which air will be blown to create the bird call sound.
Curl the lips tight around the teeth with mouth slightly open. This is the lip position needed for blowing into the hands. Try to see if you can make a whistle with the lips in this position before placing them to the thumbs.
Place the top lip above the knuckle of the thumbs and bottom lip below and blow into the cupped hands. Make sure not to cover the entire gap between the knuckles when blowing. Air needs to escape from the gap between the thumbs as well to create the proper sound.
Practice until a low whistle begins to escape through the remaining gap in the knuckles. Moving the hands and adjusting the gap between the thumbs adjusts the pitch and tone of the bird call. Try varying the blowing strength to produce a sound.
Be sure to take regular breaks while practicing. Like blowing up multiple balloons, making a bird call uses a lot of breath and can make people feel light headed or dizzy. Slowly work on your bird call instead of attempting to master it in a single day.